# Cheves Perky

Mary Cheves West Perky (1874–1940) was an American psychologist and one of the twenty-one female students who studied under Edward B. Titchener at Cornell University. She received a Ph.D. in 1910 for her groundbreaking work on visual, auditory, and olfactory imagery. Her findings have had a considerable impact by being cited by name in the title of an article as recently as 2012. According to her findings, perception is not merely a representation of the external world, but is also influenced by thoughts, expectations, and mental images. In the same year, she performed the "Banana Experiment," which demonstrated how perception and visual imagery could be confused; a phenomenon known as the Perky Effect. She concluded that mental imagery is not merely a weak form of perception, but it can directly influence our sensory perceptions. which examines the link between mental imagery and visual perception.
Perky also studied the cooperative movement, a group of organized activities aimed at providing benefits and mutual assistance among its members. Her engagement led her to become the Associate Secretary of the Cooperative League of America.

## Perky effect

The experiments performed by Perky in Titchener's lab in 1910 are considered classics in the history of psychology and mental imagery research.
She conclusively showed how when sensory input and mental imagery interact, sensory input can be mistaken for mental imagery. Now known as the Perky Effect, her research described the result when a subject's visual perception is altered by imagining a sequence of images.
To test her hypothesis,
   Perky trained her participants to look at a blank screen and try to imagine an object like a piece of fruit. She intentionally gave them the category without suggesting a specific type of fruit, then asked her participants to fixate a point on a screen in front of them and to visualize their imagined object at that location. During this process, a faint image, like a yellow crescent, was projected in soft focus just above the threshold of visibility. Typically, participants reported imagining an object matching the projected shapes, although they were unaware of the projection. Perky had led them to assume that a physical stimulus was imagined. This confusion is known as the Perky Effect.
The images were projected at a very low brightness to start and gradually increased in brightness. The participants were asked to describe the objects that corresponded to the image that was being projected.
   ...none of Perky's subjects (who ranged from a ten-year-old child to experienced introspectors of Titchener's laboratory) ever realized that they were experiencing real percepts; they took what they “saw” on the screen to be entirely the products of their imagination. However, the projections did influence their experiences.
Participants reported that they believed they were imagining the projected images rather than actually perceiving them. Additionally, they also reported “seeing” the mental images in greater detail than what was presented in the stimulus. Through her research, it has been shown that imagery can be derived from short and long-term memories due to its ability to improve recall. Perky also distinguished between "images of memory" and "images of imagination." Images of memory are personal episodic images and are associated with more eye movements and feelings of familiarity. Images of imagination are more general, have little meaning to an individual, and may be associated with feelings of surprise.
The Perky Effect, which describes the link between mental imagery and visual perception, has been a foundation for continued research in visual perception and imagery. Her studies have inspired replications and further exploration of how perception and imagery can affect things like visual acuity.

## Selected works

* Perky, Cheves West. "An experimental study of imagination." The American Journal of Psychology 21.3 (1910): 422-452.
* Perky, Cheves West. Cooperation in the United States. Intercollegiate Socialist Society, 1919.
* Perky, Cheves West. "Children in the Museum." Bulletin of the Pennsylvania Museum 27.143 (1931): 11-14.